Nuclear Science and Techniques

《核技术》(英文版) ISSN 1001-8042 CN 31-1559/TL     2019 Impact factor 1.556

Nuclear Science and Techniques ›› 2009, Vol. 20 ›› Issue (2): 65-70 doi: 10.13538/j.1001-8042/nst.20.65-70

• SYNCHROTRON TECHNOLOGY AND APPLICATIONS •     Next Articles

Evaluation of external quality factor of the superconducting cavity using extrapolation method

MA Zhenyu1,2,* MA Guangming1,2 HOU Hongtao1 YU Haibo1,2 ZHANG Rui1,2 LIU Jianfei1   

  1. 1 Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China 2 Graduate University of Chinese Academy of Sciences, Beijing 100049, China
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MA Zhenyu, MA Guangming, HOU Hongtao, YU Haibo. Evaluation of external quality factor of the superconducting cavity using extrapolation method.Nuclear Science and Techniques, 2009, 20(2): 65-70     doi: 10.13538/j.1001-8042/nst.20.65-70

Abstract:

The estimation of the external quality factor is important for designing coupling devices for the cavities. A new representation of the external quality factor calculations for single-cell cavity coupled to a coaxial transmission line is derived based on analytic analysis and numeric analysis with the help of 3D electromagnetic code, and verified with experimental measurements at room temperature. In logarithmic scale the results for the external quality factor were quasi-linear over the limited range, and the simulated and measured data could be used and extrapolated to the superconducting case. For the unpolished 1.5 GHz 3rd harmonic superconducting cavity, the discrepancy between the evaluation value and measurement result is less than 25% within an acceptable deviation.

Key words: External quality factor, Vertical testing, Superconducting cavity, Coaxial input coupler